It is not just the file size itself (storage requirements), it is the computer processing power and amount of RAM you need to do post on such images. That's not a small concern -- certainly wouldn't be last on my list. I'd like 36MP at FF and 24MP in crop mode. That is plenty MPs enough to make nice big prints...

I don't mind having 'only' 24 MP myself - I don't see it as a limitation. I'd like those pixels to be as large as possible, though... They'd be great on a uncropped 645.

I don't mind having 'only' 24 MP myself - I don't see it as a limitation. I'd like those pixels to be as large as possible, though... They'd be great on a uncropped 645.

At 16MP I still am wanting more. 24MP is probably plenty enough, but 36MP at FF still sounds good, and leaves room to still get more than we have now in crop mode. Don't think I'd feel wanting for another decade at that level...

I would be happy with 24MP, but it they went 36MP.. I would be happy with that if they were able to keep at least 6fps and descent ISO. This would out preform the D800 and probably be a very expensive FF compared to 24MP.. but maybe Pentax can keep the price down.

My K-5 14-bit files are 14-18 MB on average. The 57 MP files will be about 50-60 MB, not 100.

straight out off my K-5 the files are smaal with low iso (like 18-21 MB) or real large when iso is bumping up to 6400 and files increase in size to 25-30 MB. ONly when I export them from LigthRoom to a DNG-file they get smaller, but even then 16-19 MB is normal.

There are absolutely D800 users who don't like the file size or the in-camera processing times. Another point to consider is that a 36MP sensor will be very unforgiving towards lenses. The 16 MP APS-C sensors have this problem to, since they have the same pixel size, but it's somewhat offset by the sweet spot advantage.

As for FF vs APS-H, I would very likely buy either if it was the next Pentax Flagship, but I would somewhat regard an APS-H product as chickening out of a true commitment, and I'm afraid that the market would see it much the same.

Ron, indeed Pentax states multiple time about being about high IQ. Not only around the 645D, but also in the interviews at Photokina 2012 when asked about FF. They confirmed their high IQ goal with the AA filter less K5 that they issued.

You get an A+ for persistency. I like the APS-H idea too. With Ricoh now as a partner, who knows where or who they could course such a sensor from? Nobody of us simple mortal Pentax users can know what is being developed, for who and for what price, at all those manufacturers. Such information tends to be kept from the public. So the most used argument of the nay-sayers: "where will they source such a sensor from?" isn't really valid at all. Same goes for the argument about the high costs of such a specialty sensor.

I always love things that go straight against the mainstream; things that are very different and stand out from all the rest. Which means that I'm clearly biassed: the fact that APS-H would stand out against the great mass of FF and APS-C DSLRs already makes it interesting for me. But it even makes sense. It would keep the form factor down. Much more DA lenses are usable on it, so less new lens developement and time time required.

I just don't think they should actually call it "APS-H". Canon calls their sensor APS-C, even though everybody knows it is smaller then the regular APS-C's. maybe Pentax should use a sensor format smaller then FF and larger then APS-H, but still call it FF anyway? If it has IQ superior to any other FF in the market, then I doubt there will be any complaints.

straight out off my K-5 the files are smaal with low iso (like 18-21 MB) or real large when iso is bumping up to 6400 and files increase in size to 25-30 MB. ONly when I export them from LigthRoom to a DNG-file they get smaller, but even then 16-19 MB is normal.

Mine are recorded as .DNG. There could be an advantage to .PEF's but I'm not aware of it. Is it faster?

maybe Pentax should use a sensor format smaller then FF and larger then APS-H, but still call it FF anyway? If it has IQ superior to any other FF in the market, then I doubt there will be any complaints.

Have you been on the internet before?

Remember when Ken Rockwell said the 645D should be called the 433? Never mind that film was never 60x45, anyway...

I think I see Ron's point, especially since I'm willing to bet a lot more APS-c lenses would work on APS-c H than on FF. Imagine this...APS-c H, 24 MP, 100 lw/ph less than FF, without the colour artifacts observable with D3200 and K-5 IIs and D600 images. It would be a winner in my camp.Of course, getting rid of the false colour would be the big thing. Just from my use, I'm guessing the DA 10-17 and Sigma 8-16 and DA 18-135 would be the only ones of my lenses that wouldn't work with APS-h. I'm guessing my DA* 60-250 would, and that would be worth a ton.

The D4 does 11 fps vs the D800's 4 or 6 and the D600's 5.5, so it's a significant step above.

Although it shares the same Sports/high-ISO score as the D600/D800, the D4 can also crank it's ISO up to 204800, whereas the D600/800 max out at 25600, so the D4 probably has some extra circuitry in there to make the high-ISO look a bit better.

The AF is near identical between D4/D800 (51 point, 16 cross types etc), but the D4 can feed higher fps through the AF system, which may produce better tracking results and so on.

All of this of course highlights the big job ahead of Pentax. Just changing the sensor size won't really impress anyone unless there are other tech smarts included in the product.